Gallardo, 32, in his second stint with the team, signed a minor league deal with the Rangers in April and has been pitching for the club's Triple-A team. He had a 3.81 ERA with 40 strikeouts and 14 walks in Round Rock.
Gallardo signed with the Rangers after being released by the Cincinnati Reds. In three relief appearances with the Reds at the start of this season, Gallardo was charged with eight earned runs in 2 1/3 innings for a 30.86 ERA.
Gallardo had a 3.42 ERA in 184 1/3 innings for the Rangers in 2015. Since 2015, however, Gallardo has pitched only 251 innings, with an ERA of 5.81.
In a series of moves before Friday's game, the Rangers recalled catcher Jose Trevino from nearby Double-A Frisco even though they will be playing with 24 players because catcher Robinson Chirinos will be serving a one-game suspension due to his on-field altercation Wednesday night with the Dodgers' Matt Kemp.
The team also placed right-handed relievers Matt Bush (right elbow strain) and Chris Martin (right calf strain) on the 10-day disabled list. Martin felt a twinge in the leg while running out of the bullpen Wednesday night at the start of the scuffle.
The Rangers also recalled right-hander Yohander Mendez from Triple-A Round Rock to start Friday night's game, a day after infielder Hanser Alberto was sent back to Round Rock. Lefty reliever Brandon Mann also was recalled.
Right fielder Nomar Mazara was a late scratch from the Texas lineup because of left wrist soreness.